Ore concentration.



UNITED STATES PATENT OFFICE.

RHETHERFORD B. MARTIN, OF NEW YORK, N. Y., ASSIGNOB. T0 MINERALS SEPARATION NORTH AMERICAN CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF MARY- LAND.

ORE CONCENTRATION.

1,236,856. Specification of Letters Patent.

No Drawing.

To all whomz't may concern:

Be it known that I, RHETHERFORD B. MAR- TIN, a citizen of the United States, residing at the borough of Manhattan, in the county of New York and State of New York, have invented certain new and useful Improvements in Ore Concentration, of which the following is a specification.

This invention consists in improvements in processes of ore concentration, and has particular reference to the concentration of ores by flotation. In these processes the powdered ore is usually mixed with water, such mixture being termed the pulp, and to this pulp is added the frothing agent, consisting of an oil or oils or a soluble frothing agent or agents, or both, and the pulp is then subjected to agitation and aeration, for example, supra-aeration by air introduced from above by heating it into the pulp, or subaeration by air introduced from below through a porous medium or otherwise, as

well known in the art, the result of this aeration and agitation being that the air bubbles coursin through the pulp gather up the metalli erous particles and carry them to the surface where they form a froth. This froth may be readily floated over a lip or dam, and will thus carry the metalliferous particles away from the body of the liquid. In these processes a mineral acid, such as sulfuric acid, is in some instances used inaddition to the frothing agent, and in other instances an alkali is used in addition to the frothing agent, and these additional substances, acid or alkaline, act in some manner not clearly understood to modify the properties of the liquid and to assist the flotation of the metalliferous mineral and to retard or prevent the flota- I esses, but also concentration may be effected of ox1dized metalliferous particles, such as oxids and carbonates of copper.

It has hitherto been proposed to'treat ox- 1d1zed metalliferous particles with soluble sulfids under such conditions that the oxidized metalliferous particles are converted into or become superficially coated with metallic sulfids and are thereby rendered suitable for concentration by flotation, as in British Patent No. 26,019 of 1909, to Sulman and Picard. The procedure accordmg to my invention is wholly diflerent from that heretofore proposed, in that the oxidlzed metallic particles are not converted into or coated with sulfid particles, but are selected and concentrated as oxidized particles. For example, if the ore contains partlClBS of carbonates of copper, of the malach1te variety, green in color, these copper carbonate particles remain particles of copper carbonates throughout the process and are clearly recognizable as particles of green copper carbonates in the concentrates. I have further found that if the amount of soluble sulfid is increased above the minute quantities which I have successfully used, or if the duration of its contact with the copper carbonates is extended, or if heat is used, so as in any one or all of these instances to coat the green copper carbonate particles with the sulfid of copper produced by such conversion, which is black, that the process is seriously impaired and that as the condition of conversion into co per sulfid is approached the impairment 0 the process increases and in some instances useful froth formation is prevented.

The sulfid solution may be prepared by dissolving one or more of the commercial sulfids in water in suitable quantities, or it may be prepared, for example, by boiling in water a mixture of sulfur and one or more alkali hydrates or alkaline earth hydrates. The following are examples of the methods last referred to of preparing sulfid solutions for use in this process.

Example 1: Boil together for a period of about ten minutes the following substances:

52 parts of caustic soda 48 parts of flowers of sulfur 6000 parts of water.

Example 2: Boil together for a period of about ten minutes- Patented Aug. 14, 1917.

Application filed January 28, 1916. Serial No. 74,921.

47 parts: of lime 58 parts of flowers of sulfur 6000 parts of water.

Exam le 3: B'oil'together for a period of about fi teen minutes- 44.6 parts of lime 50.4: parts of flowers of sulfur 1 part of caustic soda.

6000 parts of water.

The resulting liquid is usually of a dark golden color when hot, and a golden yellow when cold. Some residue may be left, especialil y when the materials used are impure, which should be allowed to settle and the clear liquid decanted; or the solution may be cleared by filtration.

In the use of this: invention a small quantityof the solution, depending on the strength of the solution and on the nature of the ore, is added to the pulp either be fore or with or after the addition of the frothing agent, and before or at the beginningof the a ita-tion and aeration The best results have been generally obtained by the addition of the solution before the frothing agent. Further, an excess of the sulfid solu tion. may: cause coagulation of the ore sli'ines andmay prevent the formation of a froth and is. to beavoided.

I have found that for the treatment of 500 grams of finely powdered porph-yry copper ore, containing about 2% of copper as sulfide, 10- cubic centimeters of the solution made accordingto Example 1 (sodium polysulfid 0.03t% of the ore) in 1500 grams of water at. normal temperature, may be used with a frothing agent in the proportion of one pound tothe ton of ore, such frothing agent consisting of 90% gas tar creosote and 110% yellowpine oil. Agitation andaeration: produce a mineral froth containingthe copper sulfide of the ore, and the froth is floated oii or separated in any suitablemanner. With such treatment any copper carbonates present inthe ore are concentrated with the copper sulfid and appear inthe concentratesas copper carbonates; and an oreor tailingscontainingthe copper inthe form of carbonates without any copper sulfid's may be efi'iciently concentrated and the carbonates ofcepper-will. appear in the froth and will be separated. asconcentratesin theform of copper carbonates;

tion may beused with 1500 grams of water at normal temperature for-the treatment of 500 ams of'the-ore above referred to with the rothing agent above referred to. The proportion of the polysu-l fid in the. ore pulp will be- 0.027% of the water of the ore pulp and 0.08% of the ore.

The following is an example of carrying out my process on a large scale, the material treated being mill slimes of a porphyry copper ore, in a pulp containing four parts of water to one of the slimes. The average assay value of the slimes was about 0.9% copper, of which 0.3% was oxidized. A solution: made according to Example 3. was added to the pulp in the proportion of six gallons of the solution per ton of slimes treated, and thereafter the ii'rothing agent was added to the solution. This f'rothi-ng agent contained oil's modified-inaccordance with the process described and claimed in my application for Letters Patent filed simultaneously herewith, Serial No. M3932", and not claimed herein, that is to say,- these oi-lshad been mixed with sulfur and sub jected to high temperatures, in the neighborhood' of 200 to 350 centig-rade, in an ordinary still, and the distillates collected foruse. Pri'erto the distillation treatment, the pine oil had been mixed in the propom tion of 1300 cc. of the oil and 5 grams of sulfur, and the petroleum distillate and sulfur had been-mined in like proportions. lhis frothingagent contained 10% of light coal tar oil, 10% of pine oil modified as above described; and 80 of apetroleum distillate of 30 Baum modified as above described; and was used in the proportion of 1.7 to- 2- pounds per tonofslimes treated. Agitation and aerationprodilced a froth of concentrates which. assayed about 10% copper and taili ngs which assayed about 0.1% copper.

In theapplication of" this invention to various ores and under various conditions, the examples of'the-precess above described may be modified without departing from this invention.

I claim:

1. A process of concentrating ores which consists in submitting anorepulp to flotation separation with agitation and aeration in the presence of a soluble sullid dissolved in the pulp in an amount and under conditions of treatment so regulated as not to coat oxidized particleswith' a visible layer of sulfid, during such treatment, and by such treatmentto obtain a froth of concentrates.

2. A process of concentrating ores C01rtaining oxidized meta-ll-iferous particles which consistsi-n submitting an ore pulp of such an ore to-flotation: separation with agitation and aeration in the presence of a solublesulfid dissolved inthe ulp-in an amount and under conditions oi treatment so regulated as not tocoat oxidized particles with avisible layer of sulfi'dduring such treatment, and by such treatment to, obtaina froth of concentrates.

3. A process of concentrating ores con taining copper which consists in submitting an ore pulp of such an ore to flotation separation with agitation and aeration in the presence of a soluble sulfid dissolved in the pulp in an amount and under conditions of treatment so regulated as not to coat oxidized articles with a visible layer of .sulfid during such treatment, and by such treatment to obtain a froth of concentrates.

4. A process of concentrating ores containing oxidized copper which consists in submitting an ore pulp of such an ore to flotation separation with agitation and aeration in the presence of a soluble sulfid dissolved in the pulp' in an amount and under conditions of treatment so regulated as not to coat oxidized particles with a visible layer of sulfid during such treatment, andby such treatment to obtain a froth of concentrates.

In testimony whereof I have afiixed my signature.

RHETHERFORD B. MARTIN. Witnesses:

HENRY D. WILLIAMS, HARRY C. Lnwrs. 

